In broadcasting and audiovisual content production and distribution systems it is often necessary to confirm the identity of a video sequence at some point in a system. This is an essential feature of a monitoring process that ensures the correct operation of an automated playout system. A well-known method is to associate metadata with video frames and to compare the metadata associated with an unknown video sequence with the metadata from a known video sequence so as to enable a particular item of content to be identified. However, this relies on the presence and integrity of the metadata.
UK patent application 1402775.9 describes how metadata describing spatial and temporal characteristics of an audiovisual stream can be automatically derived from an audiovisual sequence, thus ensuring the availability of accurate metadata from an available audiovisual sequence.
International patent application WO 2009/104022 describes how spatial and temporal ‘signatures’ can be derived from audiovisual data. These types of signature, also known as ‘fingerprints’, enable video fields or frames or sequences of fields or frames to be characterised. In this specification the term fingerprint is used to designate such characterising data and the term image is sometimes used for convenience to denote either a field or a frame.